Open Letter to the Dental Profession:
Swede-Vent and Screw-Vent Surface
SWEDE-VENT AND SCREW-VENT OFFER BRÅNEMARK’S PATENTED SURFACE
Brånemark’s U.S. Patent No. 4,330,891 granted in 1982 states, "An analysis of jaw implants in homo [showed that] the bio-optimal result [could be achieved using] a biologically flawless material with a porous (i.e. micro-pitted) surface intended to face the tissue."
The Swede-Vent and Screw-Vent pure titanium implants from Core-Vent Corporation, ACCORDING TO AN INDEPENDENT EXPERT NOMINATED BY NOBELPHARMA, do provide the type of micro-pitted surface specified in Brånemark’s patent. According to Brånemark’s statements under oath to the U.S. Patent Office, this surface will provide, "inextricable anchoring in the living bone tissue." Core-Vent instituted acid etching procedures in 1986 and, during the last three years, has conducted extensive tests using SEM, EDAX and Auger analysis, and built its own Class 10,000 Clean Room facility in an attempt to perfect the cleaning process and provide the profession with a "biologically flawless" or superclean surface.
NOBELPHARMA FUNDED STUDY CONFIRMS ADVANTAGES OF ACID ETCHING SURFACE
Taussig Metallurgical Engineers Report #74305-1/August 27, 1987 (copies available from Core Vent Corporation), examined Nobelpharma implants that "had been packaged in sealed glass containers" with "a representative of the Brånemark Company being present." Examination using "scanning electron microscope and Energy Dispersion X-ray Analysis of two samples representing titanium dental implants" revealed the following:
It appeared that the grinding of the surface of the implant produced a number of titanium particles that were partially dislodged, and/or folded over onto the surface of the implant.
Energy Dispersion X-ray Analysis of this dark appearing particle revealed that the primary element was lead. in addition, there was a significant amount of tin. Other elements present were silicon, aluminum, magnesium and iron.
This particle is primarily a piece of silicon and magnesium oxide.
This particle is primarily iron.
Machined titanium surfaces are not metallurgically satisfactory and can detract from the suitability of the implants for service.
The report by Taussig Metallurgical Engineers strongly recommended to Nobelpharma to wash their implants in acid (passivation) to "eat out any metallic particles."
THE NOBELPHARMA SURFACE ANALYSIS REPORT CONCLUDED:
Brånemark implants exhibited evidence of nonmetallic particles on the surface of the implants while the implant had been sealed in glass containers.
Even though the implants have been rendered biologically sterile, the contamination of the metal surface by metallic particles had resulted in the implants being not sterile from a metallurgical point of view.
It is our opinion that the metallic particles and nonmetallic particles that we observed on the Brånemark Implant surfaces as well as the numerous areas where the apparently ground surfaces have been folded over, are not metallurgically satisfactory and can detract from the suitability of the implants for service.
The titanium surface can be and should be passivated (i.e. acid washed –– explanation added) similar to that process performed on stainless steel to eat out any metallic particles and to help reinforce the passive oxide film on the surface of the titanium.
The dentist, periodontist or oral surgeon has every right to expect that the surfaces of the implants that they are inserting are clean and free from any particles that could possibly adversely affect the serviceability of that implant.
THE CORE-VENT ANALYSIS CONFIRMS ETCHED SURFACE IS "METALLURGICALLY IMPROVED"
Taussig Laboratories recently evaluated Core-Vent Corporations’s cleaning procedures and concluded: "The general surface appearance of the Core-Vent, Screw-Vent and Swede-Vent Implants, in our opinion, appear to be metallurgically improved over that of the Brånemark implants previously examined for Nobelpharma by our laboratory because the surface has been chemically passivated (acid etched) to "eat out" any embedded metal particles. The surface of the Nobelpharma Implant is machined which causes microscopic machining laps. These laps fold over metal particles and adhere these particles to the implant surface."
The acid etching procedure used to clean the machined surfaces of the Screw-Vent and Swede-Vent implants increases the number of micro-pits in the 1-3 micron range. This is the important range Brånemark’s patent claims was shown by his research to "approach the order of magnitude of the cell diameter" and give "operation results" that were "noticeably improved."
SURFACE CONTAMINATION MAY BE CAUSE OF "SECONDARY FAILURE OF OSSEOINTEGRATION"
Albrektsson, in an article in Dental Clinics of North America, January 1986, stated: "Secondary failure of osseointegration, when a primarily achieved bone anchorage is lost, sometimes years after insertion, may depend on a slight incompatibility of the used material, an unsuitable surface finish of the implant or an overloading."